Grinding wheel guard



May 10, 1955 J. c. JOHNSON GRINDING WHEEL GUARD 2 Sheets-Sheet 1 Filed NOV. 3, 1952 I. a 1 F fzvvz/vro/q WuQWW M W ATTORNEYS May 10, 1955 Filed Nov. 5, 1952 J. C. JOHNSON GRINDING WHEEL GUARD 2 Sheets-Sheet 2 [A raw-0 W MWW 7 M W irrakwz s United States Patent GRINDING WHEEL GUARD .John Carl Johnson, Rockford, .11].

Application November 3, 1952, Serial No. 318,427 9 Claims. (Cl. 51-102 This invention relates to a guard for a portable grinding wheel.

In the use .of screw making machinery the common practice is to feed continuously into the screw making machine the wire or rod from which the screw is to be produced. During this operation successive lengths of the wire or rod are placed end-tovend and welded together at their abutting ends to provide a continuous rod or wire fed to the screw making machine. This welding is commonly an electric welding operation and produces a hard burr or flange around the periphery of the rod or wire at the .weld point which must be ground off to make the rod or wire uni-form in diameter. This grinding operation preferably :is done with a portable grinding wheel driven from a flexible shaft. The present invention is particularly directed to a guard for a portable grinding wheel for this purpose which is especially adapted for shielding the operator of the grinding wheel during this operation. However, the guard of the present invention may also be employed for other and different grinding operations, as will be apparent to those skilled in the art.

. It is, therefore, an object of the present invention to provide a novel guard for a portable grinding wheel which facilitates the use of the grinding wheel during the grinding operation and which protects the operator during the grinding operation.

It is also an object of thisinvention to provide a guard for a portable grinding wheel which has a novel handle mounting by means of which the guard and the grinding wheel may be supported and manipulated during the grinding operation with a minimum of strain on the operator.

Another object of this invention is to provide a guard for a portable grinding wheel which is of novel construc- .tion facilitating the inspection of the work piece during the grinding operation, without the necessity of first removing the guard from the work piece.

A further object of this invention is to provide a guard fora portable grinding wheel having novel structural characteristics which facilitate the guiding of the grinding wheel to the grinding position relative to the work piece and for maintaining the grinding wheel suitably located with respect to the work piece as successive portions of the work piece are being ground.

Other and further objects and advantages of the present invention will be apparent from the following description of a preferred embodiment thereof, which is illustrated in the-accompanying drawings.

In the drawings:

Figure l is a longitudinal section taken centrally through the guard of the present invention, along the line 1-1 in Fig. 2, and showing the grinding wheel in grinding engagement with the work piece;

Figure 21is a front end view of the Fig. l assembly;

Figure 3 -is a side view of the back :piece of the Fig. l guard; and

Figure 4 is a front view of the back piece of the guard.

Referring to the drawings, there is shown a rotary flex- ,ible shaft 11 driven from a suitable source of motive power, such as an electric motor, and extending loosely and rotatably through a handle 12, which forms 'a part of the guard assembly of the present invention. A chuck 13 is suitably attached in a conventional manner to the flexible shaft and is supported for rotation by the handle 12. A grinding wheel 14 is attached to the chuck 13 by means of spaced nuts 15 and 16 mounted on the threaded front end 13a of the-chuck and clamped against the back and front faces, respectively, of the grinding wheel. 'In this manner the grinding wheel is driven for rotation by the flexible shaft.

As best seen in Fig. 1, the chuck and grinding wheel are enclosed within a housing comprising tthe'front plate 17 and the back piece 18, which are separably attached together by screws 19. The back piece 18 includes a rear annular collar portion 20 which is formed with a radially inwardly extending annular shoulder 21 near its rear end. Behind this shoulder 21 the back piece is cut away to provide an annular space 22 in which are located ball bearings 23. An annular plate 24 is bolted to the rear face .of the back piece 18 to enclose the ball bearings 23 within the hpl sing. assembly. The ball bearings 23 act between the inner end of the handle 12 and the back plate -18 to permi-t the handle to be turned about its own axis relative to the housing for the grinding wheel, while maintaining the handle 12 fixed longitudinally with respect to the heming.

At the forward end of its collar portion 20 the back piece 18 is formed with a radially outwardly "extending transverse wa1l25 which is imperforate except for an approximately triangular aperture 26 at its lower end (see Figs. 2 and 4). An outer annular wall 27 extends for-ward from the outer edge of the transverse wall and extends around substantially ,theentine periphery of the grinding wheel 14. At its lower end the annular wall 27 terminates at the opposite edges of the aperture 2.6, as best seen in Figs. 2 and 4, to define an opening 27a at the bottom of the back piece for. receiving the rod 32 which is to be ground 'ofi .by the grinding wheel. Preferably the back piece 18 is of onepiece, cast aluminum construction.

The front plate ,17 of the housing includes a central forwardly protruding hub portion 28 for receiving thefor- Ward end of the spindle 13. Below this hub portion the front plate is ormed with a U-shaped rib construction which has spaced downwardly extending legs 29*and 30 Located on opposite sides ofan elongatedaperture 31 which is open at the bottom of the front piece and'whic-h =extends radially inwardly toward the hubportion-28,-terminating inwardly beyond the lower periphery of the grinding wheel 14. The aperture v31 is aligned with :the bottom opening 274 and the wider aperture 26 in the back piece, as best seen in Fig. 2, and defines therewith .a-pa ssage for receiving .the rod 32 which -is to be subjected to the action of the grinding wheel 14. From Fig. 2 it will be noted that the legs 29 and 30 define a passage for guiding the guard relative to the rod 32 as .the guard is manipulated to position the grinding wheel 1.4 inengagement with the rod 32.

In the operation of this device, the operator grips :the handle 12 and manipulates. it to cause the .U-shaped rib construction on the front piece to straddle the rod 32, with the legs 29, 30 of this rib. construction located at opposite sides of the rod and with the rod also extending freely through the aperture 26 in the back piece. During the grinding operation the grinding wheel guard may be turned about the rod to 'bring the grinding wheel into engagement with successive different portions of the periphery of the rod. During this turning of the guard .the depending legs 29 and 30 on the guard continue to straddle the rod 32, so that the guard is never fully removed from the rod throughout the entire grinding operation. It is to be-especially noted that in so turning the guard it is not necessary to turn the handle 12 correspondingly, since the rotatable mounting of the guard on the handle enables the guard to be turned in this manner merely by shifting the handle 12 bodily angularly about the rod 32. This feature is of considerable importance since it greatly facilitates the operators performance and avoids muscular fatigue in so manipulating the guard to complete the grinding operation.

The rather large aperture 26 in the back plate is of .particular advantage because it permits the operator to ing wheel from the rod but with the rod 32 still located in the guide aperture 31 formed by the legs 29 and 31}, so that the grinding operation may be resumed readily without the necessity of relocating the guard on the rod 32.

The foregoing features of structural novelty of course i do not interfere with the primary function of the guard,

While in the foregoing description and in the accornpanying drawings there is disclosed a particular preferred embodiment of the present invention, it is to be understood that various modifications, omissions and refinements departing from the disclosed form of the invention may be resorted to without departing from the spirit and scope of the present invention.

I claim:

1. A guard for a portable grinding wheel comprising a housing having an annular wall dimensioned to extend around substantially the entire periphery of the grinding wheel and formed with an opening for receiving the work piece, front and back pieces connected to said annular portion to extend substantially across the front and back faces of the grinding wheel, one of said housing pieces being formed with an aperture communicating with said 4 opening in the annular wall and extending inwardly therefrom beyond the lower periphery of the grinding wheel for visual inspection of the work piece, and the other of said housing pieces being formed at its lower end with an inwardly extending opening communicating with said tending legs on opposite sides of said inwardly extending opening to define a passage for receiving the work piece and for guiding the housing for movement toward the work piece to position the work piece at said opening in the annular portion for engagement by the grinding wheel and for retaining the housing in engagement with the work piece as the housing is turned progressively about the work piece.

2. A guard for a portable grinding wheel comprising a housing having an annular portion dimensioned to extend around substantially the entire periphery of the grinding wheel and front and back walls connected to said annular portion dimensioned to extend substantially across the front and back faces of the grinding wheel, a hollow handle for holding said housing having a lengthwise passage for rotatably receiving a grinding wheel drive shaft, bearing means between said back wall and said handle rotatably mounting said housing on said handle for free rotation about the axis of the grinding wheel. said housing being formed with an opening in said annular portion for receiving a work piece and an aperture in one of said walls communicating with said opening in said annular portion and providing spaced work guiding edges for engagement with the work piece to rotate said housing relative to said handle as the grinding wheel is moved around the work piece.

3. In a portable grinding wheel assembly, the combination of a rotary grinding wheel, a housing having an annular wall extending about substantially the entire periphery of the grinding wheel, a front wall of the housing connected to said annular wall and extending substantially across the front face of the grinding wheel, a back wall of the housing connected to said annular wall and extending substantially across the back face of the grinding wheel, a handle for holding said housing having a passage extending therethrough, a shaft secured to said grinding wheel and extending through said passage, bearing means rotatably mounting said housing on said handle for movement about the axis of said grinding wheel, said housing being formed with an opening in said annular wall for receiving a work piece, and said front and back walls having registering apertures therein communicating with said opening in the annular wall and extending therefrom inwardly beyond the lower periphery of the grinding wheel, the aperture in said front wall providing spaced work guiding edges adapted to engage the work piece and rotate the housing relative to the handle as the grinding assembly is moved around the work piece.

4. In a portable grinding wheel assembly, the combination of a rotary grinding wheel, a housing having an annular wall extending about substantially the entire periphery of the grinding wheel, a front wall of the housing connected to said annular wall and extending substantially across the front face of the grinding wheel, a back wall of the housing connected to said annular wall and extending substantially across the back face of the grinding wheel, said housing being formed with an opening in said annular wall for receiving a work piece, said back wall having an aperture communicating with said opening in said annular wall and extending therefrom inwardly beyond the lower periphery of the grinding wheel for visual inspection of the work piece, said front wall having an aperture communicating at its outer end with said opening in the annular wall, and a pair of spaced legs extending outwardly from said front wall on opposite sides of said aperture therein to define a guide passage for receiving the work piece and for guiding the housing for movement toward the Work piece to position the work piece at said opening in the annular wall of the housing for engagement by the grinding wheel and for retaining the housing in engagement with the work piece as the housing is turned progressively about opening in the annular wall and spaced outwardly exthe Work piece 5. A guard for a portable grinding wheel comprising a housing having an annular wall dimensioned to extend around substantially the entire periphery of the grinding wheel and formed with an opening for receiving the work piece, front and back walls connected to said annular wall to extend substantially across the front and back faces of the grinding wheel, said back wall being formed with an aperture communicating with said opening in the annular wall and extending therefrom inwardly beyond the periphery of the grinding wheel for visual inspection of the work piece, a handle for holding said housing, said handle being rotatably connected to said housing for free relative turning between the housing and the handle, said front wall having an aperture communicating at its outer end with said opening in the annular wall, and a pair of spaced legs extending outwardly from said front wall on opposite sides of said aperture therein to define a guide passage for receiving the work piece and for guiding the housing for movement toward the work piece to position the work piece at said opening in the annular wall of the housing for engagement by the grinding wheel and for retaining the housing in engagement with the work piece as the housing is turned progressively about the work piece.

6. A guard for a portable grinding wheel comprising a housing having an annular wall dimensioned to extend around substantially the entire periphery of the grinding wheel and formed with an opening for receiving the work piece, front and back walls connected to said annular wall to extend substantially across the front and back faces of the grinding wheel, said back wall being formed with an aperture communicating with said opening in the annular wall and extending therefrom inwardly beyond the periphery of the grinding wheel for visual inspection of the work piece, a reduced diameter collar extending rearwardly from said back Wall for enclosing a rotary chuck for driving the grinding wheel, and a hollow handle for holding said housing extending rearwardly from said collar, said handle having a lengthwise passage for receiving a flexible shaft for driving the chuck, rotary bearing means located between the collar and the handle for maintaining the handle fixed longitudinally relative to the collar and for free turning of the housing about the handle, said front wall having an aperture communicating at its outer end with said opening in the annular wall, and a pair of spaced legs extending outwar ly from said front wall on opposite sides of said aperture therein to define a guide passage for receiving the work piece and for guiding the housing for movement toward the work piece to position the work piece at said opening in the annular wall of the housing for engagement by the grinding wheel and for retaining the housing in engagement with the work piece as the housing is turned about the work piece.

7. A guard for a portable grinding wheel comprising a housing having a front portion dimensioned to substan tially enclose a grinding wheel and a reduced diameter collar extending rearwardly from said front portion for enclosing a rotary chuck for driving the grinding wheel,

said housing having a work receiving opening in the periphery thereof extending inwardly beyond the periphery of the grinding wheel, a hollow handle for holding said housing extending rearwardly from said collar, said handle having a lengthwise passage for receiving a shaft for driving the chuck, and rotary bearing means located between said collar and the handle for maintaining the handle fixed longitudinally relative to the collar and for free turning of the housing on the handle about the axis of the grinding wheel whereby said housing may rotate relative to the handle as the grinding wheel is moved around the work piece to maintain said work receiving opening in the housing in registry with the work piece.

8. A guard for a portable grinding wheel comprising a housing having an annular portion dimensioned to extend around substantially the entire periphery of the grinding wheel and front and back walls connected to said annular portion dimensioned to extend substantially across the front and back faces of the grinding wheel, a hollow handle for holding said housing having a lengthwise passage for rotatably receiving a grinding wheel drive shaft, bearing means between said back wall and said handle rotatably mounting said housing on said handle for free rotation about the axis of the grinding wheel, the ends of said annular portion of said housing terminating in spaced relation to each other to provide an opening therein for the reception of the work piece, said back wall having a visual inspection aperture therein extending from the ends of said annular portion inwardly beyond the periphery of the grinding wheel, said front wall being formed with a radially extending slot narrower than said opening in said annular portion and providing spaced work guiding edges located between said ends on the annular portion for engagement with the work piece to rotate the housing relative to the handle as the grinding wheel is moved around the work piece and maintain said ends of said annular portion and the edges of the aperture in the back wall spaced from the work piece to permit visual inspection of the work piece during the grinding operation.

9. In a portable grinding wheel assembly, the combination of a rotary grinding wheel, a housing having an annular wall extending substantially around the entire periphery of the grinding wheel and front and back walls connected to said annular wall dimensioned to extend substantially across the front and back faces of the grinding wheel, a hollow handle for holding said housing having a lengthwise passage for rotatably receiving a grinding wheel drive shaft, bearing means between said back wall and said handle rotatably mounting said housing on said handle for free rotation about the axis of the grinding wheel, said housing being formed with an opening in said annular portion for receiving a work piece and a slot in one of said walls communicating with said opening in said annular wall, said slot providing parallel work guiding edges extending outwardly of the periphery of the grinding wheel a distance greater than the spacing between said work guiding edges, said work guiding edges being adapted to engage the work piece to rotate the housing relative to the handle as the grinding Wheel is moved around the work piece to thereby maintain the opening in said annular wall in registry with the work piece.

References Cited in the file of this patent UNITED STATES PATENTS 973,894 Toomey Oct. 25, 1910 1,117,660 Gilmore Nov. 17, 1914 1,134,833 Fischer et a1. Apr. 6, 1915 2,077,281 Stevenson Apr. 13, 1937 2,097,655 DeMarche et al. Nov. 2, 1937 2,354,307 Emery July 25, 1944 2,374,988 Flohr et al. May 1, 1945 2,510,950 Blavier June 13, 1950 

